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Development of the NR 55 concept continued in 1941 with the generally similar NR 54 V1, in which reductions were made in size and weight. The engine power was reduced to 24hp and the rotor diameter to 7.8m with the engines mounted 1.2m from the centerline driving the propellers, which were 1.8m further out along rotor blade. The carburetor was never perfected to work satisfactorily and due to this no test flights were ever made. Performance with empty and loaded weights of 80 and 175kg respectively, was estimated to have a 55 mph cruising speed.

The NR 54 V2 was produced in 1941. The single-seat helicopter flew on remarkably little power. The 6.9m rotor consisted of two single blades, each of which had an 8hp motor driving a small airscrew at 6000rpm to give a torqueless drive, and the pilot's controls consisted of two levers, one to alter rotor blade pitch and the other to control the engines. The entire airframe broke down for transporting and could carried by a single man. The little ship was said to cruise at 80km/h and climb at 140m/min.

Four of the NR 54V2 machines were built before the war ended, but it is not known how close the NR 54 was to being ready for production at that point. At least one of them was brought to the USA for evaluation and is now in the collection of the National Air and Space Museum.